export function createReducer (initialState, actionHandlers) {
  return (state = initialState, action) => {
    const reduceFn = actionHandlers[action.type]
    if (!reduceFn) return state
    // Looks it works like Object.assign
    return { ...state, ...reduceFn(state, action) }
  }
}

export function dateToString(date) {
  let oDate = new Date(date) == "Invalid Date" ? new Date(Number(date)) : new Date(date),
    sYear = oDate.getFullYear(),
    sMonth = oDate.getMonth() + 1,
    sDate = oDate.getDate(),
    sHour = oDate.getHours(),
    sMinutes = oDate.getMinutes(),
    sSeconds = oDate.getSeconds();
    sSeconds = sSeconds < 10 ? '0'+sSeconds : sSeconds;
  return  sYear+ '-' + sMonth + '-' + sDate + ' ' + sHour + ':' + sMinutes + ':' + sSeconds;
}

export function getSession(key) {
  if(window.sessionStorage){
    return window.sessionStorage.getItem(key)
  }else{
    return false;
  }
}

export function setSession(key,value) {
  if(window.sessionStorage){
    window.sessionStorage.setItem(key,value)
    return true;
  }else{
    return false;
  }
}

export function delSession(key) {
  if(window.sessionStorage){
    window.sessionStorage.removeItem(key)
    return true;
  }else{
    return false;
  }
}

export function clearSession() {
  if(window.sessionStorage){
    window.sessionStorage.clear()
    return true;
  }else{
    return false;
  }
}


export function base64_encode(str){
  var c1, c2, c3;
  var base64EncodeChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  var i = 0, len= str.length, string = '';

  while (i < len){
    c1 = str.charCodeAt(i++) & 0xff;
    if (i == len){
      string += base64EncodeChars.charAt(c1 >> 2);
      string += base64EncodeChars.charAt((c1 & 0x3) << 4);
      string += "==";
      break;
    }
    c2 = str.charCodeAt(i++);
    if (i == len){
      string += base64EncodeChars.charAt(c1 >> 2);
      string += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
      string += base64EncodeChars.charAt((c2 & 0xF) << 2);
      string += "=";
      break;
    }
    c3 = str.charCodeAt(i++);
    string += base64EncodeChars.charAt(c1 >> 2);
    string += base64EncodeChars.charAt(((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4));
    string += base64EncodeChars.charAt(((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6));
    string += base64EncodeChars.charAt(c3 & 0x3F)
  }
  return string
}

export function base64_decode(str){
  var c1, c2, c3, c4;
  var base64DecodeChars = new Array(
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57,
    58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6,
    7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
    25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
    37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1,
    -1, -1
  );
  var i=0, len = str.length, string = '';

  while (i < len){
    do{
      c1 = base64DecodeChars[str.charCodeAt(i++) & 0xff]
    } while (
    i < len && c1 == -1
      );

    if (c1 == -1) break;

    do{
      c2 = base64DecodeChars[str.charCodeAt(i++) & 0xff]
    } while (
    i < len && c2 == -1
      );

    if (c2 == -1) break;

    string += String.fromCharCode((c1 << 2) | ((c2 & 0x30) >> 4));

    do{
      c3 = str.charCodeAt(i++) & 0xff;
      if (c3 == 61)
        return string;

      c3 = base64DecodeChars[c3]
    } while (
    i < len && c3 == -1
      );

    if (c3 == -1) break;

    string += String.fromCharCode(((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));

    do{
      c4 = str.charCodeAt(i++) & 0xff;
      if (c4 == 61) return string;
      c4 = base64DecodeChars[c4]
    } while (
    i < len && c4 == -1
      );

    if (c4 == -1) break;

    string += String.fromCharCode(((c3 & 0x03) << 6) | c4)
  }
  return string;
}
